SIMPLE WG T. Moran Internet-Draft Expires: November 9, 2003 S. Addagatla E. Leppanen Nokia May 11, 2003 Requirements for Presence Specific Event Notification Filtering draft-ietf-simple-pres-filter-reqs-00 Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http:// www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on November 9, 2003. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document defines a set of structured requirements whereby a presence information subscriber may select specific information to be received in the presence infomation notification sent by the notifier. The purpose is to limit the content and frequency of notifications so that only essential information on a need basis is delivered by the server. Moran, et al. Expires November 9, 2003 [Page 1] Internet-Draft Presence Filtering Requirements May 2003 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Requirements for Specification of Filters . . . . . . . . . 4 3.1 Common Syntax . . . . . . . . . . . . . . . . . . . . . . . 4 3.2 Package Identification . . . . . . . . . . . . . . . . . . . 4 3.3 Target URI . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.4 Notification Triggering . . . . . . . . . . . . . . . . . . 4 3.5 Notification Content Limiting . . . . . . . . . . . . . . . 5 4. Requirements for Uploading Rules (Operational Rules) . . . . 5 4.1 SUBSCRIBE Method . . . . . . . . . . . . . . . . . . . . . . 5 4.1.1 Retention of Filter Settings . . . . . . . . . . . . . . . . 5 4.1.2 Changing Filter Settings . . . . . . . . . . . . . . . . . . 6 4.2 Server does not Support Filters . . . . . . . . . . . . . . 6 4.3 Server does not Support Filter Settings . . . . . . . . . . 6 4.4 Server can no Longer Support Filter Settings . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . 6 6. Example Applications for Notification Filtering . . . . . . 6 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 References . . . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 7 Intellectual Property and Copyright Statements . . . . . . . 9 Moran, et al. Expires November 9, 2003 [Page 2] Internet-Draft Presence Filtering Requirements May 2003 1. Introduction SIP event notification is described in [6]. It defines a general framework for subscriptions and notifications for SIP event packages. Concrete applications of the general event framework to a specific group of events are described in [5] (user presence) and [7] (watcher information). The presence information refers to a set of presence attributes describing the availability and willingness of the user (presentity) for communication. The user makes his presence information available for other users (watchers). As the inherent usage of event packages grows, the client needs some mechanisms for controlling the event notifications at the source. Evidence of this need is found in [4]. The Internet Draft describing the Presence event package [5] mentions the possibility for a filtering. Accordingly, the SUBSCRIBE request may contain a body for filtering the presence information subscription. However, the definition of the filtering has been left out of the scope of the Internet Draft. As an example, the body of the SUBSCRIBE request may include a restriction on the set of data returned in NOTIFY requests. These mechanisms are expected to be particularly valuable to users of wireless devices. The characteristics of these devices typically include low bandwidth, low data processing capabilities, small display and limited battery power. Such devices can benefit from the ability to filter the amount of information generated at the source of the event notification. However, it is expected that the control mechanisms for event notifications add value for all users irrespectively of their device or network access characteristics. Section 3 and Section 4 of this draft propose a set of requirements whereby a client may specify which notifications it is interested in. That is, a means to specify filtering rules to be executed by the server. Section 6 provides a few example applications of notification filtering. 2. Conventions In this document, the key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' are to be interpreted as described in RFC 2119 [1] and indicate requirement levels for compliant implementations. Moran, et al. Expires November 9, 2003 [Page 3] Internet-Draft Presence Filtering Requirements May 2003 3. Requirements for Specification of Filters The following requirements relate to the creation of filters (rules). 3.1 Common Syntax A common set of constructs MUST be defined for the creation of rules. There MUST be a common set of operations that follow a common syntax. The user MUST be possible to define different rules for different purposes using a common filtering mechanism. 3.2 Package Identification A means is REQUIRED whereby the user may specify the package the rules apply to. 3.3 Target URI It MUST be possible for the watcher to indicate the target presentity or presentity list to which a certain filter criteria is applied. It MUST be possible to support filtering also in presence list subscriptions. Is MUST be possible to specify different filter criteria for individual presentities than the other presence list members in a presence list subscription case. 3.4 Notification Triggering This chapter presents requirements for specifying the desired conditions for when notifications are to be sent to the client. The scope of the 'when' part is to allow a possibility for the user to specify such rules for the notification triggering where the criteria is based on the presence information, e.g., the value of the status element. The notification triggering criteria would override the default trigger conditions of the server/service as defined in the package when they are within the server's local policy constraints. It MUST be possible to specify logical expressions based on the value of elements defined in the package for the purpose of when to send notifications. This covers expressions (tests) related to the change of an element's value, and reaching a certain value of an element. It MUST be possible to construct expressions that combine multiple Moran, et al. Expires November 9, 2003 [Page 4] Internet-Draft Presence Filtering Requirements May 2003 tests. 3.5 Notification Content Limiting This chapter presents requirements for specifying the content to be sent in the notifications. It MUST be possible for the watcher to specify the presence information elements [2] (XML elements and/or attributes) to be delivered in the notification. The specified elements MUST be able to cover also extensions to PIDF formated presence information, see for example [3]. E.g. the following two cases must be possible: o The watcher MUST be able to define a criteria which allows the complete tuple and all information within a tuple to be transmitted. o The watcher MUST be able to define a criteria which result notifies to contain values only for defined attributes. It MUST be possible to specify logical expressions based on the value of elements defined in the package for the purpose of determining what to send in the notification. The existence of an element SHOULD be considered as a criterion. It MUST be possible to construct expressions that combine multiple tests. 4. Requirements for Uploading Rules (Operational Rules) It MUST be possible for the watcher to upload the rules to the server (notifier) and know the status - accepted or rejected. 4.1 SUBSCRIBE Method Placing filtering rules in the body of the subscription MUST be supported. Other means of delivering the filtering rules to the event server MAY be supported. E.g. it should be possible for the rules to be (permanently) stored in the server, as in a presence list case. 4.1.1 Retention of Filter Settings The server MUST retain the uploaded filter setting for the duration of the subscription. Moran, et al. Expires November 9, 2003 [Page 5] Internet-Draft Presence Filtering Requirements May 2003 4.1.2 Changing Filter Settings It MUST be possible to change the filter settings during a subscription. It MUST be possible for the watcher to reset the filter settings to the service (server) defined default. 4.2 Server does not Support Filters If the server does not support filters (the content type) then it MUST be able to indicate so in a response. 4.3 Server does not Support Filter Settings It MUST be possible for the server to explicitly indicate that it does not support or understand the filter settings. This indication MAY include a reason about the refusal of the filter settings. 4.4 Server can no Longer Support Filter Settings The server MUST be able to terminate the subscription if the active filter is no longer applicable due to a policy in the server. 5. Security Considerations Further security requirements over [5] have not yet been identified. 6. Example Applications for Notification Filtering 1. A watcher wishes to get to know presentity's availability and willingness for messaging (e.g. IM and MMS). 2. A watcher is interested in getting information about the communication means and contact addresses the presentity is currently available for communication. 3. A watcher requires a notification if the state of a buddy has changed to 'open'. 4. A Subscriber only wants to be notified when the presentity's location is Dallas or Fort Worth. The notification should include the vehicle license, driver name, and city. 5. A Basic location tracking service requires notification when the presentity's cell id changes. The notification should include the cell id. Moran, et al. Expires November 9, 2003 [Page 6] Internet-Draft Presence Filtering Requirements May 2003 7. Acknowledgements The authors would like to thank Hisham Khartabil, Mikko Lonnfors, Juha Kalliokulju, Aki Niemi, Jose Costa-Requena and Markus Isomaki for their valuable input. References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Sugano, H., "CPIM Presence Information Data Format", draft-ietf-impp-cpim-pidf-07.txt, December 2002. [3] Schulzrinne, H., "RPIDS -- Rich Presence Information Data Format for Presence Based on the Session Initiation Protocol (SIP)", draft-schulzrinne-simple-rpids-01.txt, February 2003. [4] Kiss, K., "Requirements for Presence Service based on 3GPP specifications and wireless environment characteristics", draft-kiss-simple-presence-wireless-reqs-02, February 2003. [5] Rosenberg, J., "Session Initiation Protocol (SIP) Extensions for Presence", draft-ietf-simple-presence-10.txt, January 2003. [6] Roach, A., "Session Initiation Protocol (SIP)-Specific Event Notification", RFC 3265, June 2002. [7] Rosenberg, J., "A Watcher Information Event Template-Package for the Session Initiation Protocol (SIP)", draft-ietf-simple-winfo-package-05.txt, January 2003. Authors' Addresses Tim Moran 2800 Britt Drive Argyle, Texas 76226 USA Phone: +1 972 849 8821 EMail: tl_moran@att.net Moran, et al. Expires November 9, 2003 [Page 7] Internet-Draft Presence Filtering Requirements May 2003 Sreenivas Addagatla Nokia 6000 Connection Drive Irving, Texas 75039 USA Phone: +1 972 374 1917 EMail: sreenivas.addagatla@nokia.com Eva Leppanen Nokia P.O BOX 785 Tampere Finland Phone: +358 7180 77066 EMail: eva-maria.leppanen@nokia.com Moran, et al. 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Expires November 9, 2003 [Page 9] Internet-Draft Presence Filtering Requirements May 2003 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Moran, et al. Expires November 9, 2003 [Page 10]